editing disabled

actual atomic mass: 4.002602
actual atomic mass: 4.002602

The most common isotope of Helium is He-4, which is produced by alpha decay of heavier radioactive elements. As its isotope notation says, it has four neutrons. Because its electrons completely fill the s-orbital, He-4 has an unusally stable nucleus. www.chemicalelements.com/elements/he.html
http://en.wikipedia.org/wiki/Isotopes_of_helium


external image Home%20Button.png